Add the "zoom" function.

[spline3.git] / src / Grid.hs

diff --git a/src/Grid.hs b/src/Grid.hs
index 1a436acdc00d9276ceb1e25b7080355577822bf3..63b2cfa122bc6ba5bbb9d496b77f1a00466eebb6 100644 (file)
--- a/src/Grid.hs
+++ b/src/Grid.hs
@@ -4,10 +4,13 @@
 module Grid
 where
 
-import Cube (Cube(Cube))
+import Test.QuickCheck (Arbitrary(..), Gen, Positive(..))
+
+import Cube (Cube(Cube), find_containing_tetrahedra)
 import FunctionValues
 import Misc (flatten)
 import Point (Point)
+import Tetrahedron (polynomial)
 import ThreeDimensional (contains_point)
 
 
@@ -20,6 +23,13 @@ data Grid = Grid { h :: Double, -- MUST BE GREATER THAN ZERO!
           deriving (Eq, Show)
 
 
+instance Arbitrary Grid where
+    arbitrary = do
+      (Positive h') <- arbitrary :: Gen (Positive Double)
+      fvs <- arbitrary :: Gen [[[Double]]]
+      return (make_grid h' fvs)
+
+
 -- | The constructor that we want people to use. If we're passed a
 --   non-positive grid size, we throw an error.
 make_grid :: Double -> [[[Double]]] -> Grid
@@ -72,3 +82,29 @@ find_containing_cubes g p =
     where
       all_cubes = flatten $ cubes g
       contains_our_point = flip contains_point p
+
+
+
+zoom :: Grid -> Int -> [[[Double]]]
+zoom g scale_factor
+    | fvs == [[[]]] = []
+    | head fvs == [[]] = []
+    | otherwise =
+        [[[f p | i <- [0..scaled_zsize],
+                 let i' = scale_dimension i,
+                 let j' = scale_dimension j,
+                 let k' = scale_dimension k,
+                 let p = (i', j', k') :: Point,
+                 let c = (find_containing_cubes g p) !! 0,
+                 let t = (find_containing_tetrahedra c p) !! 0,
+                 let f = polynomial t]
+                 | j <- [0..scaled_ysize]]
+                   | k <- [0..scaled_xsize]]
+  where
+    scale_dimension :: Int -> Double
+    scale_dimension x = (fromIntegral x) / (fromIntegral scale_factor)
+
+    fvs = function_values g
+    scaled_zsize = ((length fvs) - 1) * scale_factor
+    scaled_ysize = (length (head fvs) - 1) * scale_factor
+    scaled_xsize = (length (head $ head fvs) - 1) * scale_factor